Garlic for fleas, hating on cats, attacking mail carriers, colorblindness -- those are just a few of the 20 absurd myths busted here.

Dog myths have been around since the domestication of dogs, and some of them stick around even today. Which ones are true and which ones are full of hot air? Here we list the 20 most ridiculous dog myths we see time and time again — and then debunk them one by one.

Myth #1: Only male dogs hump other dogs.

My last two female dogs can easily prove this one wrong. They both took a ride on each other, people and objects. They were both female and were spayed as soon as they were old enough. Research tells us the behavior is an act of dominance and is perfectly normal.

Myth #2: Indoor dogs don’t need heartworm prevention.

Tell that to the mosquito that just flew inside your house and eyed your dog like a buffet station. Mosquitoes spread heartworms, and they can land on your pet indoors or outdoors. Heartworm prevention is very important to your dog’s health. A dog infected with heartworms faces a long, expensive treatment process, and that’s only if the damage isn’t too severe when found.

Myth #3: Giving your dog leftovers will reduce waste.

While your trash can or bin won’t fill as quickly, you could be feeding your dog harmful bones, high-fat content foods and even ingredients that are toxic to your dog. Cooked bones are especially known for splitting and splintering, and just imagine what those splinters could do to your dog’s internal organs. Other issues involve gastrointestinal problems and pancreatic concerns. Do your dog a favor and stick to dog food and treats. If you want to reduce waste, try composting instead.

Myth #4: Dogs eat grass only if they are sick.

Ancestors such as wolves ate an entire animal — stomach contents included. Small prey animals usually fed off of grasses and berries, and that’s most likely where the taste for grass originated. Most recent research indicates that quite simply put, dogs just like to eat grass. If the grass is treated with chemicals then it could be hazardous to your pet. Some vets do believe that dogs will intentionally consume large amounts of grass to induce vomiting if they feel unwell or have consumed something toxic, but this should not be consistent behavior. Same goes for too much of a good thing; eating too much grass (or too often) may incur a trip to the vet’s office.

Myth #5: A dog will be fine in the car as long as you crack the windows.

Never, ever do this, even if you think you are only running out for a minute. Even in cool temperatures the heat inside a vehicle can rise quickly, and this is even more dangerous in warmer temperatures. Leaving your dog inside the vehicle is as bad as placing your dog in an oven and turning up the heat. Read this vet’s article to find out what happens to a dog’s body when it overheats, most often seen in dogs left in vehicles. Be warned — it’s graphic.

Leaving your dog in a car can also be against the law in some states.

The video below offers information about what happens to a dog left in a car (don’t worry, the dog is safe the entire time), what bystanders do and what people should do if they see a dog left in a vehicle:

Myth #6: A dog’s mouth is cleaner than a human’s mouth.

Did you not see your dog lick his butt or eat the neighbor’s dog’s poop? While it’s true most of the germs in a dog’s mouth are dog-specific and harmless, that does not include where your dog’s mouth might have been. Licking the concrete, eating grass, lapping up dirty rain water, sampling the neighboring dog’s poop and all kinds of undigestibles you would never eat yourself can make their way onto your face or in your mouth.

Dogs that do not get their teeth brushed can also have tarter buildup and excess bacteria. Another possibility is worms. Humans can get worms from dogs without noticing it until symptoms appear. Imagine that the poop your dog sampled has microscopic worms that are easily transmitted. Even just a lick of the butt can have the same effect. Still want to offer a sloppy wet kiss?

Myth #7: Dogs are colorblind.

Myth #8: Calculate a dog’s age by multiplying human years times seven.

Recent research and media have reported this method as outdated. By the time your dog is one year old she’s already a teenager, and extra years get added as the dog gets older. Check our chart here for exact conversions (cat years included too).

Myth #9: A wagging tail is a sign of a happy dog.

This is not always true. Tail wagging can also be a sign of fear, anxiety or impending aggression. The tail may wag slower, erratically or while inverted on a dog’s back. Look at the total body language before approaching a dog you don’t know.

Myth #10: Female dogs need to have one litter of puppies before they can be spayed.

This myth is one of the worst — and one that keeps overpopulation a constant problem. Dogs do not have to produce a litter before they can be altered. There is no evidence that proves this method offers any health benefits, yet there is ample evidence that spaying reduces the frequency of future health problems while reducing overpopulation.

Not all dogs are natural mothers, and keep in mind that you can’t predict a litter size. Imagine you allowed your dog just that one first litter and out comes 11 puppies. When you can’t care for them or find homes or adopters, they end up at the shelter.

Myth #11: Breeds on the banned list are always aggressive and will attack anyone given the chance.

Myths like these only add fuel to the fire that is breed-specific legislation (BSL). Any dog can be aggressive without proper (or with improper) socialization and training. The CDC concluded that no dog is born inherently dangerous or vicious, and the American Temperament Test Society results show some of these “aggressive and dangerous” dogs higher up on the friendly end than other dogs we think are harmless.

My dog is one bulky and strong canine. She will play, wrestle, let me take her bones away or play with her food — anything. She’s not aggressive in the slightest way and is awesome with kids (my niece and nephew can attest to that fact). She is, however, very protective against strangers. If you tried to harm me or enter my home uninvited, I’d almost guarantee she’d take a chunk out of you. Does that make a dog worthy of being labeled dangerous? Not in my book.

Myth #12: All large dogs are dangerous.

This one is just plain nuts. Have you read our recent breed profile of the Newfoundland? Those dogs can get upwards of 150 pounds or more and they are as harmless as a stuffed teddy bear. My aunt’s two Great Danes think they are tiny lapdogs, and many other large dogs can easily debunk this myth. Other than accidentally knocking someone over because of their size, many large dogs are just puppies in big packages.

Myth #13: Dogs get all the exercise they need in the backyard.

Dogs go outside to do their business and maybe investigate around, but they are natural pack animals and want to be by your side. Unless you’re outside in the yard with them encouraging play and exercise, plan to take your dog for a daily walk, hike, swim or any activity that gets them moving. Regular exercise helps promote stable weight and increases health benefits.

Myth #14: You can’t teach an old dog new tricks.

This has to be the oldest myth about older dogs, and it’s still not true. Many older dogs may suffer limited hearing or vision that prevents them from learning or following commands easily, but age is not a determining factor for tricks or training.

My dog is 12 years old (equal to a 64-year-old human), and she’s pretty set in her ways. She has a high prey drive and was chasing the wild rabbits that ventured into the yard, and I was able to teach her the “leave it” command. She’s now happy to sit outside and just watch them, and the rabbits are out nibbling in the yard every day now.

Need more proof? Check out this video of MythBusters putting it to the test:

Myth #15: A dry or warm nose is a sign your dog is sick.

Dog noses are not always cool and wet, and occasional dryness is perfectly normal. There are also many reasons your dog may have a dry nose. A runny nose, colorful discharge or a crusty buildup is not good, so head to the vet if you notice these symptoms.

Myth #16: Dogs hate mail carriers.

Most dogs are protective of their family and their home, and the dog recognizes the mail carrier as a stranger who needs to keep a distance. Unless you have had the same mail carrier for years and your dog has had a chance to socialize with him or her, expect a bark.

Myth #17: All dogs hate cats.

The myth

While it’s true some dogs may give chase and the cat may hiss and flick a paw or two, this myth is false and easy to disprove.

The reality

Myth #18: A little chocolate won’t hurt.

Chocolate can be toxic and life-threatening to dogs. As little as 1 ounce of dark chocolate may be enough to kill a small dog. Keep the chocolate for yourself and nobody gets hurt. (For more on chocolate, read this article from Dr. Deb.)

Garlic may keep pests at bay during a short walk, but it should not be seen as a preventive. Opinions differ on the consumption of garlic by dogs, but most agree that trace amounts are okay. The difficulty with garlic is knowing at what amount it becomes toxic to your dog. It is best to avoid giving your dog garlic for this reason and stick with your vet’s recommendations for flea and tick prevention. Too much garlic can cause an anemic reaction, gastrointestinal problems and red blood cell damage, according to the ASPCA. Our suggestion? Save it for the vampires and zombie apocalypse.

Photos: japrea (top), ablebody, sabianmaggy/Flickr

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